Technological advancements and high standard of living together bring the trend of 3C hi-tech electronic products toward light weights, compactness and versatility. Hence, silicon carbide (SiC), III-nitrides (such as GaN, AlN), and the like are developed to become semiconductor materials for use in the manufacturing of various electronic device. In this regard, silicon carbide (SiC) and III nitrides not only has high physical strength and high chemical inertness, but also manifests excellent electronic characteristics, including hardness, high breakdown critical electric field strength, wide band gaps, high saturation drift velocity, and high thermal stability.
Semiconductor manufacturers employ physical vapor transport (PVT) and physical vapor deposition (PVD) to grow crystals from silicon carbide and III nitrides as well as manufacture chips by mass production. PVT involves subliming powder of silicon carbide (SiC) and III nitrides in a muffle heating zone and speeding up movement of the gaseous silicon carbide (SiC) and III nitrides to a seed crystal by temperature gradient to undergo crystal growth process. However, the quality of crystals grown by PVT depends on the temperature of the crystal growth process. Hence, the prior art proposes controlling the temperature of the PVT-based crystal growth process through improvement in the apparatuses used. For instance, U.S. Pat. No. 5,968,261 discloses forming a cavity in a graphite crucible and then applying a thermally insulating material to the inner surface of the cavity to increase the efficiency of dissipation of heat from the rear of a seed crystal. US20060213430 discloses changing the distance between a seed crystal and a seed holder to control conductive heat transfer between the seed crystal and the seed holder such that the conductive heat transfer dominates the effect of radiative heat transfer between the seed crystal and the seed holder. U.S. Pat. No. 7,351,286 discloses positioning a seed crystal to reduce the bend of and stress on the seed crystal. U.S. Pat. No. 7,323,051 discloses positioning a seed crystal by a porous material at the rear thereof and features a gas-phase blocking layer for reducing sublimation of the seed crystal. U.S. Pat. No. 7,524,376 discloses growing an aluminum nitride crystal with a thin-walled crucible and by PVT to reduce thermal stress. U.S. Pat. No. 8,147,991 discloses controlling efficiency of heat transfer by adjusting the position of a seed holder so as for the seed holder to fit the surface of a seed crystal right.
Improvement in thermal field distribution, as disclosed in the prior art above, is predicted by simulating the thermal field of the crystal growth environments with simulation software and thus is never free of errors. There is a difference in particle diameter distribution between raw materials (such as silicon carbide), and thus there is a difference in the thermal field between silicon carbide crystal growth experiments. For the previously mentioned reasons, the aforesaid thermal field simulation fails to evaluate the actual thermal field temperature distribution in the crucible (crystal growth furnace).
Hence, it is important for the industrial sector to develop a device for measuring distribution of thermal field in a crucible so as to measure the actual distribution of thermal field in the crucible, eliminate temperature-dependent interference with crystal growth, adjust the distribution of thermal field in the crucible, prevent material-induced or apparatus-induced interference, achieve optimal distribution of thermal field in the crucible, and thus grow high-quality crystals.